公开(公告)号：EP1768242A4

公开(公告)日：2008-05-28

申请号：EP04732460

申请日：2004-05-12

Applicant: MERSTECH INC

Inventor： SHIMADA RYUICHI ,  SUMITANI HIDEO ,  TAKAKU TAKU ,  ISOBE TAKANORI

IPC: H02M5/293 ,  H02M1/00 ,  H02M1/42

CPC classification number: H02P27/16 ,  H02M1/4208 ,  H02M2003/1555 ,  Y02B70/126 ,  Y02P80/112 ,  Y10T307/62 ,  Y10T307/631

Abstract: An AC power supply unit for regenerating magnetic energy in which power factor of an AC load can be improved while realizing reductions in cost and size. The AC power supply unit comprises a bridge circuit consisting of four reverse conductivity type semiconductor switches, a capacitor connected between the DC terminals of the bridge circuit and storing magnetic energy when a current is interrupted, an AC voltage source connected in series with an inductive load and being inserted between the AC terminals of the bridge circuit, and a control circuit performing on/off control of each reverse conductivity type semiconductor switch by applying a control signal to the gate thereof, characterized in that the control circuit performs control such that a pair of reverse conductivity type semiconductor switches on a diagonal out of four reverse conductivity type semiconductor switches constituting the bridge circuit are respectively turned on/off simultaneously, and the other pair out of two sets of pair is turned off when one pair is turned on, and the control signal is switched in synchronism with the voltage of the AC voltage source.